High-power high-brightness 980 nm lasers with >50% wall-plug efficiency based on asymmetric super large optical cavity

Abstract

High-power high-brightness super large optical cavity laser diodes with an optimized epitaxial structure are investigated at the wavelength of 980 nm range. The thicknesses of P- and N-waveguides are prudently chosen based on a systematic consideration about mode characteristics and vertical far-field divergences. Broad area laser diodes show a high internal quantum efficiency of 98% and a low internal optical loss of 0.58 cm^-1. The ridge-waveguide laser with 7 μm ridge and 3 mm cavity yields 1.9 W single spatial mode output with far-field divergence angles of 6.8° in lateral and 11.5° in vertical at full width at half maximum under 2 A CW operating current. The corresponding M² values are 1.77 and 1.47 for lateral and vertical, respectively, and the corresponding brightness is 76.8 MW‧cm^-2‧sr^-1. The far-field divergence angles with 95% power content are in the range of 24.7° to 26.1° across the whole measured range.